Antioxidant Activities of Vitamins E and C in a Novel Liposome System

Abstract

A new model liposome made of anionic and cationic surfactants and methyl linoleate was used to investigate the antioxidant activity of vitamins E and C. The spontaneous vesicle formation was demonstrated by transmission electron microscopy with a negative‐staining technique. The model liposome was kept in the dark at a temperature of 310K and the progress of the methyl linoleate oxidation was evaluated by measurement of conjugated dienes hydroperoxides and malondialdehydes. The results indicate that vitamins E and C could inhibit the lipid oxidation as a chain‐breaking antioxidant, respectively. Further, the combination of vitamins E and C causes an antioxidant synergistic effect in the model system. It is shown that the model liposome can be suitable for simulating biomembranes as a convenient and useful alternative model system. PRACTICAL APPLICATIONS Phospholipid vesicles, which are produced from the aqueous dispersion of single‐component phospholipids, when formed in vitro are usual models of biomembranes for investigation of the antioxidant activities in biological systems. However, such lipid vesicles are not the equilibrium aggregation state and can be considered as metastable structures of high kinetic stability but thermodynamically nonstable. The present study shows that the lipid vesicles formed in an aqueous mixture of cetyltrimethylammonium bromide, sodium dodecyl sulfonate and methyl linoleate by using sonication could be used as appropriate models for in vitro mimicking the behavior of biological membranes and those oxidation processes occurring within them. This model liposome is a stable and convenient alternative model system. Furthermore, the comparison of the antioxidant effects of vitamins E and C in this study may be helpful to understand the mechanism of antioxidant action in biological system.

Interplay between Structure and Fluidity of Model Lipid Membranes under Oxidative Attack

“…This result clearly shows that vitamin E bound to the membrane effectively inhibited the oxidation of lipids and accounts satisfactorily for the observed intact membrane fluidity. 48 Despite our result not excluding a contribution from increased stability due to the incorporation of vitamin E, the result indicates that this mechanism might not be essential to maintain fluidity for membranes under the attack of oxidative reagents.…”

“…This observation is consistent with the corresponding result of membrane fluidity (Figure 6A) thereby confirming that antioxidation is the underlying mechanism for vitamin C to inhibit the increased membrane fluidity induced by hydroxyl radical. Although this conclusion is conventional wisdom, 47,48 this result demonstrates that correlated Raman and FCS measurements provide a structural account of the modification of membrane fluidity under oxidative attack.…”

Oxidative status and the severity of clinical symptoms in patients with post-traumatic stress disorder

“…38 The results were calculated and expressed as concentration of MDA (µmol/L) using the extinction coefficient of 156,000 Lmol −1 cm −1 . 39…”

“…Serum MDA concentrations were measured using the modified TBARS method described by Anguloa et al 37 and Botsoglou et al 38 The results were calculated and expressed as concentration of MDA (mmol/L) using the extinction coefficient of 156,000 Lmol À1 cm À1 . 39…”

Grass carp peptides hydrolysed by the combination of Alcalase and Neutrase: Angiotensin‐I converting enzyme (ACE) inhibitory activity, antioxidant activities and physicochemical profiles

“…As transitory intermediates, the hydroperoxides could degrade into different chemical compounds containing MDA. In literature, the MDA index has been used as a sensitive indictor for monitoring the secondary oxidation products (Xie & Ji, ). In fact, the reduction in the concentration of MDA corresponds to the increase in the capability of the antioxidant.…”